Tostado is also accused in Mexico of killing Carl Smith, Brown's sometime boyfriend and father of her child, who was shot in the head in Tijuana in April 2010. Brown was alleged to have paid Tostado, who goes by the nickname of "Superman," and another man, Gabriel Campa-Mayen, to kill Smith.

Campa-Mayen was acquitted at trial of the drug charges he faced related to the case, however - a rare loss for federal prosecutors.

Tostado was picked up on Friday in Chula Vista, Calif., and was being held in the San Diego Metropolitan Correctional Center pending extradition to Baltimore. An attorney is not listed for him in court records.

In an affidavit filed in 2010, authorities said that Smith was involved in the murder and dismemberment of Michael Knight in a Rosedale apartment. Knight had been holding $1 million for the organization and lost $250,000 after it was seized by police, and he was beaten, tied up and stabbed to death in a bathtub, then dismembered with a power-type saw. His remains were disposed of in the Loch Raven and Liberty Road areas.

Baltimore County police began to suspect Brown was linked to Knight's killing, and she and Smith fled to Mexico to regroup. Julio Carlos Meza-Mendez, then an official at the Mexican consulate in Tucson, Ariz., used his diplomatic status to get the pair across the border, federal authorities have claimed in court filings.

But Smith considered leaving the crew, and prosecutors say he was soon killed, with Meza-Mendez calling Brown to confirm the killing had occurred. Meza-Mendez pleaded guilty in January 2013 to conspiring to distribute more than 100 kilograms of marijuana.

Brown was sentenced to life in prison in March, and is appealing her sentence.